first inaugural address four years ago, we're back in the first few hours of president obama's second term. four years ago, of course, at a time of crisis, he offered hope and promised change four years later, some of that change in himself, jodi cantor has written about it. her headline -- she's written a bestseller, "the obama's" with us also tonight david gergen, he's seen presidential change from nixon to clinton. you've been writing about the obamas since they first came into congress. the role that michelle obama plays for president obama in the white house, what is that role and how has it changed? >> it's about the overall vision, this is not a first lady who bursts into the west wing saying, we have to do this and this and this. >> i heard she's rarely seen. >> rarely seen, the constructive thing to remember, is that she never wanted her husband to be a politician. and if he was going to be a politician, she didn't want him to become a regular politician. they talk a lot about getting past the washington noise, about why they came to washington. what they wanted to accomplish